By using someone else''s ideas, people are infringing the copyright law and committing plagiarism
Copyright law protects the original authors of a work from unauthorized reproduction/use. When using the ideas from an author, people need to refer the original author.
Mohammed, R. A., Shaaban, O. M., Mahran, D. G., Attellawy, H. N., Makhlof, A., & Albasri, A. (2015). Plagiarism in medical scientific research. Journal of Taibah University Medical Sciences, 10(1), 6-11. Doi: http://dx.doi.org/10.1016/j.jtumed.2015.01.007